docs: def dataframe(self):
          """
          Returns a ``pandas DataFrame`` containing all other relevant class
          properties and values where each index is a different season plus the
          career stats.
          """
          temp_index = self._index
          rows = []
          indices = []
          if not self._season:
              return None
          for season in self._season:
              self._index = self._season.index(season)
              rows.append(self._dataframe_fields())
              indices.append(season)
          self._index = temp_index
          return pd.DataFrame(rows, index=[indices])